This invention relates to a machine tool such as a milling machine.
Although various machine tools ahve been used and proposed, they have only a single spindle head. Users recently need various capabilities such as a low-speed heavy cutting or high-speed light cutting of work due to different work materials. For example, work made of non-ferrous metal such as aluminum is cut at a high speed.
Users can buy either machine tools for use in high-speed light cutting or machine tools for use in low-speed heavy cutting. For example, it both high-speed light cutting and low-speed heavy cutting must be carried out, two types of machine tools must be separately bought.